In Europe during the Dark Ages, eleven-year-olds Edmund and Elspeth must again battle ancient, evil forces, when Elspeth's magical sword guides them to the lair of Loki, a monstrous being whom the sword was forged to kill.

Thialfi, the Norse thunder god's goat boy, tells how he inadvertently helped the giant Thrym to steal Thor's magic hammer, the lengths to which Thor must go to retrieve it, and his own assistance along the way.

"It's not every day that you find a famous weatherwoman bound by magic to a tree deep in the woods. Or discover that the weatherwoman is in fact Sunna, the Norse Goddess of the Sun, and one of the seven day guardians who keep time in order. But that's just what happens to Buzz and his new friend Mary"--Dust jacket flap.

It is Hero Day at school, so the Avengers go to school to help the class learn, but somebody is messing things up for the class. It is Loki, and he did all those things because he felt left out. He fixes everything and everyone has fun the rest of the day.